Self-centering crossfolder

ABSTRACT

The present invention relates to a laundry cross-folding machine and also to a method of cross-folding a workpiece. The machine includes a pair of workpiece detectors operatively connected both to a clamp and one of a pair of squeeze rollers. A workpiece to be folded is fed in offset relationship relative to a fold plane disposed between the squeeze rollers. The shorter side of the workpiece is clamped whilst the longer side introduced into the fold plane. Thereafter, once the workpiece has been located in a correct position, the clamp is released so that the whole of the workpiece is folded into the fold plane.

United States Patet [191 McDermott SELF-CENTERING CROSSFOLDER [75] Inventor: Derrick McDermott,Brighouse,

' England [73] Assignee: Thomas Broadbent & Sons Limited,

Yorkshire. England 22 Filed:' Mar. 14,1972

21 Appl. No.; 234,519

[52] US. Cl. 270/69 [51] Int. Cl B65h 45/04 [58] Field Of Search 270/61 R, 62, 68 R, 69, 270/83, 84, 85

[56] References Cited UNITED STATES PATENTS 3,079,143 2/1963 Jensen 270/68 R 1113.772 12 /1963 Malott et al. 270/69 3,229,973 l/l966 Cornwall 270/69 FOREIGN PATENTS OR APPLICATIONS l 2l7,l57 5/1970 Great Britain Mar. 19, 1974 Primary ExaminerWm. H. Grieb Attorney, Agent, or Firm-Diller, Brown, Ramik & Wight [57] ABSTRACT The present invention relates to a laundry crossfolding machine and also to a method of cross-folding a workpiece. The machine includes a pair of workpiece detectors operatively connected both to a clamp and one of a pair of squeeze rollers. A workpiece to be folded is fed in offset relationship relative to a fold plane disposed between the squeeze rollers, The shorter side of the workpiece is clamped whilst the longer side introduced into the fold plane. Thereafter, once the workpiece has been located in a correct position, the clamp is released so that the whole of the workpiece is folded into the fold plane.

6 Claims, 5 Drawing Figures SELF-CENTERING CROSSFOLDER The present invention relates to a folding machine and particularly relates to a cross folding laundry machine for cross folding flat workpieces such as sheets.

Laundry folding machines are well-known in the art. One difficulty with such machines however, is ensuring that a workpiece is folded about a desired fold line.

One solution to this problem, where transverse folding is required, has been described and claimed in the Applicants prior British Pat. No. 1217157. The arrangement described in this prior application however is not suitable for use with cross folding machines.

If it is desired to cross fold a sheet in half for example and the sheet is not fed centrally to the folding machine, the fold will not occur at the halfway position giving rise to an asymetrically folded sheet. Clearly this is undesirable aesthetically.

According to the present invention there is provided a folding machine which comprises a pair of squeeze rollers arranged on either side of a fold plane and located below a workpiece feed conveyor, a first of the rollers on one side of the machine being mounted for pivotal movement between workpiece driving and nondriving positions, first means located above the conveyor in line with the fold plane and arranged upon actuation to introduce part of the workpiece between the squeeze rollers and into the fold plane, a pair of detectors each disposed a selected distance on either side of the fold plane, each detector being connected to a clamp located above the conveyor on said one side the first squeeze roller and second means located above the conveyor offset from said fold plane and on said one side and arranged, upon actuation, to urge the workpiece against the second roller, the arrangement being such that operation of the detector on said one side actuates respectively the clamp, to clamp the workpiece on said one side pivots the first roller to its non-driving position and actuated said second means so that the workpiece on the side of the fold plane remote from said one side is driven by the second roller into the fold plane, operation of the other detector being arranged to deactuate said clamp, said second means, and to return the first roller to its workpiece driving position to complete the passage of the workpiece between the squeeze rollers into the fold plane and folded in a manner predetermined by the selected positioning of the detectors with reference to the fold plane.

If a second fold is desired, an additional squeeze roller may be provided beneath one, but preferably the second squeeze roller.

Preferably the first means comprises an air blast pipe, the detectors each comprise a light and photocell arrangement and the second means comprises a traction blow pipe. Alternatively the second means may comprise a pivotally mounted auxiliary roller operable to urge the workpiece against the second squeeze roller.

Also according to the present invention there is provided a method of cross folding a workpiece which comprises feeding the workpiece in offset relation to a fold plane, subjecting the workpiece to first means disposed above the workpiece and in line with the fold plane to introduce part of the workpiece between a pair of squeeze rollers and into the fold plane, detecting the passage of the shorter side of the workpiece into the fold plane with a first detector spaced a selected distance from said fold plane and clamping the workpiece in response tooperation of said detector, continuing to feed the longer side of the workpiece into the feed plane whilst detecting its passage with a second detector spaced a selected distance from said fold plane, operation of said second detector being arranged to release the shorter side of the workpiece to allow the complete passage of the workpiece between the squeeze rollers into the fold plane and folded in a manner predetermined by the selected positioning of the detectors with reference to the fold plane.

The invention will now be further described by way of example with reference to the accompanying drawings, which illustrate the sequential steps in the folding of a workpiece in which:

FIG. 1 is a diagrammatic sectional elevation illustrating the position of a workpiece in a folding machine constructed in accordance with the invention at the commencement of a folding operation;

FIGS. 2 to 4 inclusive are diagrammatic illustrations similar to FIG. 1 showing successive positions of the workpiece.

FIG. 5 is a fragmentary diagrammatic sectional elevation of a modified form of the invention.

The drawings illustrate across folding machine constructed in accordance with the invention and including a conveyor 10 for supporting a workpiece 12. In the drawings the conveyor and the workpiece are travelling out of the paper as viewed.

A pair of squeeze rollers 14 and 16 are rotatably mounted below the conveyor, and the roller 14 is also pivotally mounted at 20 on an arm 18.

The vertical plane which extends between the squeeze rollers will be referred to hereafter as the fold plane. A fold air blast pipe designated 22 is shown above the conveyor and the workpiece and lying with its axis in the fold plane. A traction blow pipe 24 is also shown above the conveyor and workpiece and lies with its axis offset to the right of the fold plane as viewed. The compressed air supplies to both the blast pipe 22 and the traction blow pipe 24 are valve controlled as for example by solenoid operated valves (not shown).

A pair of detectors 26 and 28 are shown equally spaced either side of the fold plane. The detectors each conveniently comprise a light source and detecting photocell. However, feeler switches may be used if desired. Both detectors are connected respectively to a clamp 30, the pivotal arm 18 and the valves controlling operation of the blast pipes 22 and 24 by suitable electrical and mechanical connections (not shown).

In operation a flat workpiece to be folded is fed along the conveyor 10 offset to the left of the fold plane as viewed as may be seen in FIG. 1. At the appropriate time the fold air blast pipe 22 is operated to initially fold the workpiece and introduce it between the rotating squeeze rollers 14, 16 and into the fold plane as may be seen in FIG. 2.

As the workpiece continues to be drawn between the squeeze rollers 14, 16 its right hand edge passes through the detector 26 which causes the clamp 30 to be actuated to hold the right hand section of the workpiece stationary on the conveyor 10. The squeeze roller 14 is also pivoted about its pivot point 20 to its nondriving position, the air blast pipe 22' is-deactuated and the blow pipe 24 actuated. The air jet issuingfrom the blow pipe 24 is directed to frictionally engage the workpiece against the squeeze roller 16 which drives the left hand half of the workpiece around the squeeze roller 16 into the fold plane as maybe seen in FIG. 3. Finally the left hand edge of the workpiece passes through detector 28 which causes the clamp 30 to release the right hand edge of the workpiece, deactuation of blow pipe 24 and the squeeze roller 14 to return to its driving position, as is illustrated in FIG. 4. The workpiece is then free to complete its passage between the squeeze rollers 14, 16 folded about a predetermined fold line determined by the selected positioning of the detectors 26, 28 with reference to the fold plane.

It will be appreciated that in the examples shown the workpiece has been folded about a halfway position, but by altering the position of the detectors the workpiece could be folded in any selected position.

In an alternative embodiment of the invention the second means comprises a pivotally mounted auxiliary roller 32 which replaces the flow pipe 24 is operable in lieu thereof to urge the workpiece against the second squeeze roller and into the fold plane. I claim:

1. A folding machine which comprises a workpiece feed conveyor, a fold plane extending transversely of said conveyor, a pair of squeeze rollers arranged one on either side of said fold plane and located below said workpiece feed conveyor, a first of said squeeze rollers on one side of the fold plane being mounted for movement between workpiece driving and non-driving positions, first means located above the conveyor in line with the fold plane and actuable to introduce part of the workpiece between the squeeze rollers and into the fold pane, a pair of detectors each disposed a selected distance on either side of the fold plane for detecting an edge of the workpiece, a clamp located above the conveyor on said one side, connection means connecting each said detector with said clamp, second means located above the conveyor and offset from said fold plane for urging the workpiece against the second squeeze roller, said detector on said one side when actuated being operable to actuate respectively the clamp to clamp the workpiece on said one side, to move the first roller to its non-driving position, and to actuate said second means to move the workpiece on the side of the fold plane remote from said one side into engagement with said second roller to be driven by the second roller into the fold plane, the other detector being operable to deactuate said clamp and said second means and to return the first roller to its workpiece driving position cooperating with said second roller to complete the passage of the workpiece between the squeeze rollers into the fold plane with the workpiece being folded in a manner predetermined by the selected positioning of the detectors with reference to the fold plane.

2. A folding machine as set forth in claim 1 wherein said first means comprises an air blast pipe and said second means comprises a traction blow pipe.

3. A folding machine as set forth in claim 1 wherein said detectors each comprise a light source and photocell arrangement.

4'. A folding machine as set forth in claim 1 wherein said second means comprises a pivotally mounted auxiliary roller operable to urge the workpiece against said second squeeze roller.

5. A method of cross-folding a workpiece which comprises the steps of feeding the workpiece to a position extending transversely through a predetermined fold plane in off center relation so as to have a shorter side, subjecting the workpiece to first means disposed above the workpiece to introduce an intermediate part of the workpiece between a pair of driven rollers and into the fold plane, continuing the feeding of the workpiece into the fold plane detecting the passage of the edge of the shorter side of the workpiece towards the fold plane with a first detector spaced a selected distance from said fold plane and clamping the shorter side of the workpiece in response to operation of said detector, continuing to feed the longer side of the workpiece into the fold plane while detecting its movement with a second detector spaced a selected distance from said fold plane, operation of said second detector being arranged to release the shorter side of the workpiece to allow the complete passage of the workpiece between the driven rollers into the fold plane and folded in a manner predetermined by the selected positioning of the detectors with reference to the fold plane.

6. A folding machine which comprises a generally horizontal workpiece feed conveyor, a generally vertical fold plane lying transverse to said feed conveyor, a pair of driven rollers arranged one on opposite sides of said fold plane and located below said workpiece feed conveyor, first means located above the conveyor and generally between said driven rollers for introducing an intermediate part of the workpiece between the driven rollers and into the fold plane, a pair of detectors each disposed a selected distance on either side of the fold plane for detecting workpiece edges, clamp means located above the conveyor on one side of said fold plane and operable in response to the detection of an edge of an associated portion of the workpiece by one of said detectors for clamping the workpiece portion against movement into said fold plane, second means located above the conveyor and arranged to cooperate with' that one of said driven rollers on the opposite side of said fold plane from said clamp means to continue the feeding of the workpiece into said fold plane, and the other of said detectors being operable when detecting the passage of the edge of the associated portion of the workpiece to release said clamp means and to allow both portions of the workpiece uniformly into said fold plane.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,797, 20 Dated March 19, 1974 Inventor-(g) DERRICK MCDERMOTT It is certified that error appears in the above-identified patent and that said Letters Patentare hereby corrected as shown below:

On the information sheet, column 1, between Items [21] and [52] there should be added:

[30] FOREIGN APPLICATION PRIORITY DATA March 22, 1971 Great Britain .7,526/71 Signed and sealed this 24th day of September 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. Attesting Officer Ca MARSHALL DANN Commissioner of Patents FORM (10'69) uscoMM-Dc wan-P69 D18. GOVERNMENT PRINTING OFFICE 1 I969 U-'3G6'-33, 

1. A folding machine which comprises a workpiece feed conveyor, a fold plane extending transversely of said conveyor, a pair of squeeze rollers arranged one on either side of said fold plane and located below said workpiece feed conveyor, a first of said squeeze rollers on one side of the fold plane being mounted for movement between workpiece driving and non-driving positions, first means located above the conveyor in line with the fold plane and actuable to introduce part of the workpiece between the squeeze rollers and into the fold pane, a pair of detectors each disposed a selected distance on either side of the fold plane for detecting an edge of the workpiece, a clamp located above the conveyor on said one side, connection means connecting each said detector with said clamp, second means located above the conveyor and offset from said fold plane for urging the workpiece against the second squeeze roller, said detector on said one side when actuated being operable to actuate respectively the clamp to clamp the workpiece on said one side, to move the first roller to its non-driving position, and to actuate said second means to move the workpiece on the side of the fold plane remote from said one side into engagement with said second roller to be driven by the second roller into the fold plane, the other detector being operable to deactuate said clamp and said second means and to return the first roller to its workpiece driving position cooperating with said second roller to complete the passage of the workpiece between the squeeze rollers into the fold plane with the workpiece being folded in a manner predetermined by the selected positioning of the detectors with reference to the fold plane.
 2. A folding machine as set forth in claim 1 wherein said first means comprises an air blast pipe and said second means comprises a traction blow pipe.
 3. A folding machine as set forth in claim 1 wherein said detectors each comprise a light source and photocell arrangement.
 4. A folding machine as set forth in claim 1 wherein said second means comprises a pivotally mounted auxiliary roller operable to urge the workpiece against said second squeeze roller.
 5. A method of cross-folding a workpiece which comprises the steps of feeding the workpiece to a position extending transversely through a predetermined fold plane in off center relation so as to have a shorter side, subjecting the workpiece to first means disposed above the workpiece to introduce an intermediate part of the workpiece between a pair of driven rollers and into the fold plane, continuing the feeding of the workpiece into the fold plane detecting the passage of the edge of the shorter side of the workpiece towards the fold plane with a first detector spaced a selected distance from said fold plane and clamping the shorter side of the workpiece in response to operation of said detector, continuing to feed the longer side of the worKpiece into the fold plane while detecting its movement with a second detector spaced a selected distance from said fold plane, operation of said second detector being arranged to release the shorter side of the workpiece to allow the complete passage of the workpiece between the driven rollers into the fold plane and folded in a manner predetermined by the selected positioning of the detectors with reference to the fold plane.
 6. A folding machine which comprises a generally horizontal workpiece feed conveyor, a generally vertical fold plane lying transverse to said feed conveyor, a pair of driven rollers arranged one on opposite sides of said fold plane and located below said workpiece feed conveyor, first means located above the conveyor and generally between said driven rollers for introducing an intermediate part of the workpiece between the driven rollers and into the fold plane, a pair of detectors each disposed a selected distance on either side of the fold plane for detecting workpiece edges, clamp means located above the conveyor on one side of said fold plane and operable in response to the detection of an edge of an associated portion of the workpiece by one of said detectors for clamping the workpiece portion against movement into said fold plane, second means located above the conveyor and arranged to cooperate with that one of said driven rollers on the opposite side of said fold plane from said clamp means to continue the feeding of the workpiece into said fold plane, and the other of said detectors being operable when detecting the passage of the edge of the associated portion of the workpiece to release said clamp means and to allow both portions of the workpiece uniformly into said fold plane. 